1. Field of the Invention
This invention relates to partitioning agents, or coating agents, for use in connection with drag reducing agents, and in particular, alpha olefin monomer partitioning agents used in methods for improving flow of hydrocarbons through conduits, particularly pipelines. The invention also relates to methods for making improved drag reducing agents.
2. Description of Related Art
Generally speaking, the flow of liquid in a conduit, such as a pipeline, results in frictional energy losses. As a result of this energy loss, the pressure of the liquid in the conduit decreases along the conduit in the direction of the flow. For a conduit of fixed diameter, this pressure drop increases with increasing flow rate. When the flow in the conduit is turbulent (Reynold""s number greater than about 2100), certain high molecular weight polymers can be added to the liquid flowing through the conduit to reduce the frictional energy losses and alter the relationship between pressure drop and flow rate. These polymers are sometimes referred to as drag reducing agents (xe2x80x9cDRAsxe2x80x9d), and they interact with the turbulent flow processes and reduce frictional pressure losses such that the pressure drop for a given flow rate is less, or the flow rate for a given pressure drop is greater. Because DRAs reduce frictional energy losses, increase in the flow capability of pipelines, hoses and other conduits in which liquids flow can be achieved. DRAs can also decrease the cost of pumping fluids, the cost of equipment used to pump fluids, and provide for the use of a smaller pipe diameter for a given flow capacity. Accordingly, an ongoing need exists to formulate improved drag reducing materials.
While various polymerization methods, reactants, and partitioning agents have been published in the patent literature, many of those methods utilize expensive partitioning agents that adversely effect the hydrocarbons transported through the conduit. In many, if not all, instances, these partitioning agents remain in the hydrocarbon stream thereby fouling the hydrocarbon and decreasing the number of uses of the hydrocarbon and/or the effectiveness of the use of the hydrocarbon. In certain aspects, the present invention overcomes one or more of the above-mentioned shortcomings.
While various partitioning agents have been used in connection with certain drag reducing agents, the inventors are not aware of any patents or publications showing alpha olefin monomers as being used as partitioning agents in connection with drag reducing agents (DRAs). For example, U.S. Pat. Nos. 4,720,397; 4,789,383; 4,826,728; 4,837,249; 5,244,937; 5,449,732; 5,504,131; 5,504,132; 5,539,044; and 6,172,151 disclose certain partitioning agents, but do not disclose or suggest the alpha olefin monomer partitioning agents of the present invention.
In accordance with the invention the foregoing advantages have been achieved through the present process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent, the process comprising: contacting alpha olefin monomers with a catalyst in a reactant mixture, wherein the reactant mixture includes at least one alpha olefin monomer partitioning agent; and polymerizing the alpha olefin monomers, wherein during the polymerization, at least a portion of the alpha olefin monomer polymerize in the reactant mixture to provide a polyalphaolefin.
A further feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the catalyst may be a transition metal catalyst. Another feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the transition metal catalyst may be a Ziegler-Natta catalyst. An additional feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the Ziegler-Natta catalyst may be titanium trichloride. Still another feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the reactant mixture may include at least one co-catalyst. A further feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the at least one co-catalyst may be selected from the group consisting of alkylaluminoxanes, halohydrocarbons, diethylaluminum chloride, and dibutylaluminum chloride. Another feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the alpha olefin monomers may comprise homopolymers, terpolymers or copolymers. An additional feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the alpha olefin monomers may comprise co-polymers of 1-hexene and 1-dodecene alpha olefins or co-polymers of 1-octene and 1-tetradodecene alpha olefins. Still another feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the polyalphaolefin may be an ultra-high molecular weight polyalphaolefin having an inherent viscosity of at least about 10 deciliters per gram and is amorphous with substantially no crystalline particles. A further feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the at least one alpha olefin monomer partitioning agent may be selected from the group consisting of C20-C60 alpha olefin monomers.
In accordance with the invention the foregoing advantages have also been achieved through the present drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent.
A further feature of the drag reducing agent is that the at least one alpha olefin monomer partitioning agent may be selected from the group consisting of C20-C60 alpha olefin monomers.
In accordance with the invention the foregoing advantages have also been achieved through the present drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent formed by contacting alpha olefin monomers with a catalyst in a reactant mixture having at least one alpha olefin monomer partitioning agent; and polymerizing the alpha olefin monomers, wherein during the polymerization, at least a portion of the alpha olefin monomers polymerize in the reactant mixture to provide a polyalphaolefin.
In accordance with the invention the foregoing advantages have also been achieved through the present drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent formed by contacting alpha olefin monomers with a catalyst in a reactant mixture; polymerizing the alpha olefin monomers, wherein during the polymerization, at least a portion of the alpha olefin monomers polymerize in the reactant mixture to provide a polyalphaolefin; and mixing the polyalphaolefin with at least one alpha olefin monomer partitioning agent.
In accordance with the invention the foregoing advantages have also been achieved through the present process for reducing drag in a conduit, comprising: forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent, wherein the drag reducing agent is formed by contacting alpha olefin monomers with a catalyst in a reactant mixture having at least one alpha olefin monomer partitioning agent; polymerizing the alpha olefin monomers, wherein during the polymerization, at least a portion of the alpha olefin monomers polymerize in the reactant mixture to provide a polyalphaolefin; and introducing the drag reducing agent into the conduit.
In accordance with the invention the foregoing advantages have also been achieved through the present process for reducing drag in a conduit, comprising: forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent, wherein the drag reducing agent is formed by contacting alpha olefin monomers with a catalyst in a reactant mixture; polymerizing the alpha olefin monomers, wherein during the polymerization, at least a portion of the alpha olefin monomers polymerize in the reactant mixture to provide a polyalphaolefin; mixing the polyalphaolefin with at least one alpha olefin monomer partitioning agent; and introducing the drag reducing agent into the conduit.
In accordance with the invention the foregoing advantages have also been achieved through the present process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent, the process comprising: contacting alpha olefin monomers with a catalyst in a reactant mixture; polymerizing the alpha-olefin monomers, wherein during the polymerization, at least a portion of the alpha olefin monomers polymerize in the reactant mixture to provide a polyalphaolefin; and mixing the polyalphaolefin with at least one alpha olefin partitioning agent.
A further feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the at least one alpha olefin partitioning agent may be selected from the group consisting of C20-C60 alpha olefin monomers. Another feature of the process for forming a drag reducing agent comprising a polyalphaolefin and at least one alpha olefin monomer partitioning agent is that the process may further comprise the step of cryogrinding the polyalphaolefin and at least one alpha olefin partitioning agent.
The alpha olefin monomer partitioning agents, methods of reducing drag in a conduit, and methods of forming drag reducing agents have the advantages of: decreasing the cost of production of drag reducing agents having partitioning agents; and decreasing the instances of hydrocarbon fouling caused by partitioning agents.